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How many familial relationship testing results could be wrong

NCJ Number
PLoS Genetics Volume: 16 Issue: 8 Dated: 2020
Date Published

Since it is reasonable to estimate that about 15 million family relationship cases have been tested globally, the current study examined how many familial relationship testing results could be wrong.


With so many cases, it is not uncommon to observe some cases that may have either included unrelated individuals as a certain relationship (i.e., false positive) or excluded truly related individuals as unrelated (i.e., false negative).  A kinship relationship is usually evaluated by comparing the likelihoods of observing the genetic data given two alternative hypotheses (i.e., likelihood ratio [LR]): an individual is related to another individual in a defined relationship versus the two individuals unrelated. The higher the LR, the more supported is the proposed relationship. In addition, the lower the LR (typically <1), the more support there is for the unrelated hypothesis. Studies [10–11] have evaluated the false conclusion rates in parent-child and full-sibling testing, using the 13 CODIS loci. Following the same approach, the current study evaluated the false conclusion rates of the common relationship testing with the current commercial kits using the common AABB LR thresholds. Pedigrees were simulated as described by Ge and colleagues for various relationships (standard trio, parent-child, full-sibling, half-sibling, first cousin, and unrelated), and LRs were calculated for the simulated relationships using the same method as Ge and colleagues. In total, more than 60,000 cases could have been wrongly concluded using the markers in the Identifier kit. Most of the false interpretations were related individuals being misinterpreted as unrelated, particularly for the parent-child and more distant relationships. In contrast, it is unlikely to identify unrelated individuals as close relatives. (publisher abstract modified)

Date Published: January 1, 2020